Thickness monitoring of graphene on SiC using low-energy electron diffraction

TL;DR

This study investigates the use of low-energy electron diffraction (LEED) as an in-situ method to monitor the thickness of epitaxial graphene on SiC, focusing on the intensity ratio of diffraction spots.

Contribution

It demonstrates that LEED intensity ratios can effectively determine graphene thicknesses from 1 to 3 monolayers during growth.

Findings

LEED intensity ratio correlates with graphene thickness

Effective for 1-3 monolayer graphene

Considers effects of thickness distribution

Abstract

The formation of epitaxial graphene on SiC is monitored in-situ using low-energy electron diffraction (LEED). The possibility of using LEED as an in-situ thickness monitor of the graphene is examined. The ratio of primary diffraction spot intensities for graphene compared to SiC is measured for a series of samples of known graphene thickness (determined using low-energy electron microscopy). It is found that this ratio is effective for determining graphene thicknesses in the range 1 to 3 monolayers. Effects of a distribution of graphene thicknesses on this method of thickness determination are considered.